As nice and easy it is to predict the DAT scores are going higher and higher, but the average intellegence of dental students will remain the same no matter what they study or whatever it is they do.
Sure "better" study material is available, so if the national AA average was 17-18 3 years ago, today it might jump up to a whopping 18.5 to 19 but it WILL level off and stay there until they make the DATz easier.
As far as competition goes, yeh, its getting pretty competitive, but there is always a good balance going on. If dentistry is going to become number # 1 in competition, then Medical school go down and vise versa.
I really think, with the heavy competition going on, an applicant needs to apply to more than 15 schools to stand a good chance (unless you get 25+ DAT and 3.5+ GPA and a **** load of shadowing hours).